Image pickup apparatus

ABSTRACT

An image pickup apparatus including a first photoelectric conversion circuit that has a photoelectric conversion area and is used for performing focus adjustment; a second photoelectric conversion circuit that has a photoelectric conversion area and is used for performing exposure amount adjustment; and a control circuit for controlling a power supply such that power is supplied to the first photoelectric conversion circuit and the second photoelectric conversion circuit independently, in which the first photoelectric conversion circuit and the second photoelectric conversion circuit are formed on a same semiconductor substrate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image pickup apparatus having aphotoelectric conversion function.

2. Related Background Art

FIG. 11 is a block diagram showing an example of an autofocus (AF)sensor circuit for multipoint distance measurement which is used in aconventional single-lens reflex camera. An AF sensor using this AFsensor circuit was published by the inventors of this application in theInstitute of Image Information and Television Engineers Technical ReportVol. 25, No. 28, pp. 1 to 6, Mar. 2001. In FIG. 11, reference numeral900 denotes a semiconductor chip (semiconductor substrate); 901, an AFsensor circuit block; 902, an analog circuit block; and 903, a digitalcircuit block.

In this AF sensor, the AF sensor circuit block 901 is composed of eightlinear sensor circuits 1A (1B) to 8A (8B) to enable seven-point distancemeasurement (cross distance measurement in the center). The analogcircuit block 902 is composed of AGC circuits 1 to 8 for controllingaccumulation time of each linear sensor circuit, a signal amplifyingcircuit 902A for amplifying a signal from the AF sensor circuit block902 to output the signal, a band gap circuit (reference voltagegeneration circuit) 902B for generating a reference voltage, and anintermediate voltage generation circuit 902C for generating voltagesrequired in sensor circuits and analog circuits.

The digital circuit block 903 consists of an input/output communicationcircuit (I/O) for communicating with a microcomputer, a timing generatorcircuit (T/G) for generating a drive pulse of a sensor, and amultiplexer circuit (MPX) for selecting various analog signals. Sincehigh-speed autofocus is required in a single-lens reflex camera, an AFsensor realizes a high-speed operation by driving the eight linearsensor circuits and the AGC circuits in parallel.

However, in the above-mentioned conventional autofocus sensor, currentconsumption in operation is increased by driving each circuitsimultaneously. Although a significant problem is not caused in asingle-lens reflex camera because a battery with a large currentcapacity can be mounted thereon, since only a battery with a smallcurrent capacity can be mounted on a compact camera, a battery life ofthe compact camera is extremely reduced.

In addition, AE and AF in the compact camera are those of an externalmeasurement system unlike a TTL system of the single-lens reflex camera.Thus, an unnecessary AF sensor circuit may operate depending upon a zoomrange of a photographing lens used in the compact camera (a distancemeasurement point of an AF sensor is located outside a photographingrange).

SUMMARY OF THE INVENTION

An object of the present invention is to reduce current consumption.

In order to attain the above-mentioned object, according to an aspect ofthe present invention, there is provided an image pickup apparatuscomprising:

a first photoelectric conversion circuit that has a photoelectricconversion area and is used for performing focus adjustment;

a second photoelectric conversion circuit that has a photoelectricconversion area and is used for performing exposure amount adjustment;and

a control circuit for controlling a power supply such that power issupplied to the first photoelectric conversion circuit and the secondphotoelectric conversion circuit independently,

in which the first photoelectric conversion circuit and the secondphotoelectric conversion circuit are formed on the same semiconductorsubstrate.

Further, according to another aspect of the present invention, there isprovided an image pickup apparatus comprising:

first and second photoelectric conversion circuits, each of whichincludes a photoelectric conversion area; and

a control circuit which, according to an operation of a zoom lens formagnifying and reducing an object image to be picked up, switchesbetween a mode in which power is not supplied to the first photoelectricconversion circuit and power is supplied to the second photoelectricconversion circuit and a mode in which power is supplied to the firstand second photoelectric conversion circuits.

Further, according to still another aspect of the present invention,there is provided an image pickup apparatus comprising:

first and second photoelectric conversion circuits, each of whichincludes a photoelectric conversion area and a logarithmic compressioncircuit;

third and fourth photoelectric conversion circuits provided on one sideof the first and second photoelectric conversion circuits, each of whichhas a plurality of photoelectric conversion areas and a reading-outcircuit for reading out peak signals of the plurality of photoelectricconversion areas;

fifth and sixth photoelectric conversion circuits provided on the otherside of the first and second photoelectric conversion circuits, each ofwhich has a plurality of photoelectric conversion areas and areading-out circuit for reading out peak signals of the plurality ofphotoelectric conversion areas; and

a control circuit for controlling a power supply such that power is notsupplied to the first, third, and fifth photoelectric conversioncircuits and power is supplied to the second, fourth, and sixthphotoelectric conversion circuits,

in which the first to sixth photoelectric conversion circuits are formedon the same semiconductor substrate.

Further, according to yet still another aspect of the present invention,there is provided an image pickup apparatus comprising:

a first photoelectric conversion circuit including a photoelectricconversion area and a logarithmic compression circuit;

a second photoelectric conversion circuit that is provided on one sideof the first photoelectric conversion circuit and has a plurality ofphotoelectric conversion areas and a reading-out circuit for reading outpeak signals of the plurality of photoelectric conversion areas; and

a control circuit for controlling a power supply such that power issupplied to the first photoelectric conversion circuit and the secondphotoelectric conversion circuit independently,

in which the first and second photoelectric conversion circuits areformed on the same semiconductor substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is comprised of FIGS. 1A and 1B illustrating block diagramsshowing a structure of a first embodiment of a solid-state image pickupapparatus for photometry and distance measurement according to thepresent invention;

FIG. 2 is a layout plan view of the first embodiment of the presentinvention;

FIG. 3 is comprised of FIGS. 3A and 3B illustrating a circuit diagramshowing an AF sensor circuit of the first embodiment;

FIGS. 4A, 4B, 4C and 4D are diagrams for explaining operation andnon-operation of the AF sensor circuit of the first embodiment;

FIG. 5 is a circuit diagram showing an AE sensor circuit of the firstembodiment;

FIGS. 6A, 6B and 6C are diagrams showing an AGC circuit of the firstembodiment;

FIGS. 7A, 7B and 7C are diagrams for explaining a relationship betweenzoom ranges at photographing time and operating AE sensor circuits andAF sensor circuits of the first embodiment;

FIG. 8 is comprised of FIGS. 8A and 8B illustrating a block diagramshowing a structure of a second embodiment of the present invention;

FIG. 9 is a layout plan view of the second embodiment of the presentinvention;

FIG. 10 is a block diagram showing an embodiment of an image pickupapparatus using the solid-state image pickup apparatus for photometryand distance measurement of the present invention; and

FIG. 11 is a block diagram showing an autofocus sensor for multipointdistance measurement of a conventional example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be hereinafter described indetail with reference to the accompanying drawings.

First Embodiment

FIGS. 1A and 1B are block diagrams showing a structure of a firstembodiment of a solid-state image pickup apparatus for photometry anddistance measurement of the present invention. FIG. 2 is a layout planview of the solid-state image pickup apparatus of the first embodiment.The solid-state image pickup apparatus for photometry and distancemeasurement of this embodiment is provided with a photometry function(function for exposure amount adjustment) in addition to a distancemeasurement function (function for focus adjustment). In these figures,reference numeral 100 denotes a semiconductor chip (semiconductorsubstrate); 101, an AF sensor circuit block that has a photoelectricconversion area and is used for performing focus adjustment; 103 and104, an AE sensor circuit block that has a photoelectric conversion areaand is used for performing exposure amount adjustment; 105, an analogcircuit block; and 106, a digital circuit block. These blocks areintegrated on the semiconductor chip 100.

The AF sensor circuit block 101 is composed of seven pairs of AF sensorcircuits 102. As shown in FIGS. 1A and 1B, the seven pairs of AF sensorcircuits 102 are constituted by seven pairs of horizontal linear sensorsof horizontal linear sensors L1A and L1B as one pair, and in the samemanner, horizontal linear sensors L2A and L2B, L3A and L3B, L4A and L4B,L5A and L5B, L6A and L6B, and L7A and L7B.

As shown in FIG. 2, the AF sensor circuit block 101 is arranged on bothsides of the semiconductor chip 100 of a substantially rectangularshape, and one horizontal linear sensor of FIGS. 1A and 1B correspondsto one AF sensor circuit 102 of FIG. 2. That is, the horizontal linearsensors L1A to L7A of FIGS. 1A and 1B correspond to the seven AF censorcircuits 102 on the left side in FIG. 2, respectively, and thehorizontal linear sensors L1B to L7B of FIGS. 1A and 1B correspond tothe seven AF sensor circuits 102 on the right side in FIG. 2,respectively. The respective AF sensor circuits 102 include aphotodiode. Symbols A1 to A7 in the left and right of FIG. 2 each denotethis photodiode.

The AE sensor photodiode area 103 and the AE sensor circuit block 104are shown as one block in FIGS. 1A and 1B. However, as shown in FIG. 2,the AE sensor photodiode area 103 is arranged in the central part of thesemiconductor chip 100, and the AE sensor circuit block 104 is arrangednext to the AE sensor photodiode area 103. As shown in FIG. 2, the AEsensor photodiode area 103 is divided into sixteen areas and constitutedby seven photodiodes for spot photometry S1 to S7, four photodiodes forwide-angle photometry W1 to W4, four photodiodes for normal photometryM1 to M4, and one photodiode for telephotographic photometry T.

Here, as shown in FIGS. 1A and 1B, the AE sensor circuit block 104includes AE sensor circuits S1 to S7, AE sensor circuits W1 to W4, AEsensor circuits M1 to M4, and an AE sensor circuit T. All of these arecurrent/voltage logarithmic transformation type AE sensor circuits. Inaddition, among these AE sensor circuits, the AE sensor circuits S1 toS7 correspond to the photodiodes S1 to S7 of the AE sensor photodiodearea 103 of FIG. 2, respectively, the AE sensor circuits W1 to W4correspond to the photodiodes W1 to W4, respectively, the AE sensorcircuits M1 to M4 correspond to the photodiodes M1 to M4, respectively,and the AE sensor circuit T corresponds to the photodiode T. Inaddition, the AE sensor circuit block 104 includes an Is (diode reversecurrent) compensation circuit 104a and a signal amplifying circuit 104b.

The analog circuit block 105 is arranged next to the AE sensorphotodiode area 103 as shown in FIG. 2, and is composed of AGC circuits1 to 7 for controlling an accumulation time of each of the AF sensorcircuits 102, a band gap circuit (reference voltage generation circuit)105 a for generating a reference voltage, an intermediate voltagegeneration circuit 105 b for generating an intermediate voltage, and asignal amplifying circuit 105 c for amplifying an output from the AFsensor circuits.

The digital circuit block 106 is arranged next to the analog circuitblock 105 as shown in FIG. 2, and is composed of an input/outputcommunication circuit (I/O) for communicating with a microcomputer (notshown), an AF sensor circuit, an AE sensor circuit, a timing generatorcircuit (T/G) for generating a drive pulse for each of the AGC circuits,and a multiplexer circuit (MPX) for selecting various analog signals.Operation and non-operation of the AF sensor circuit, the AE sensorcircuit, and the AGC circuit are controlled by a control signal from theT/G circuit under control of the microcomputer as described later indetail.

FIGS. 3A and 3B show specific circuit diagrams of the AF sensor circuits102 of FIGS. 1A and 1B. In the figure, reference numeral 1 denotes PNjunction photodiodes for performing photoelectric conversion; 2, resetMOS transistors for resetting potentials of the PN junction photodiodesto VRES; 3, differential amplifying circuits for amplifying chargesgenerated in the PN junction photodiodes; 4, MOS capacitors formemorizing output voltages of the differential amplifying circuits 4; 5,MOS transistors for memory switches; and 6, source follower circuits foramplifying and reading out charges held in the MOS capacitors 4. Itbecomes possible to suppress offset variation and gain drop of outputvoltages by feeding back outputs of the source follower circuits 6 tothe differential amplifying circuits 3.

Reference numeral 7 denotes clamp capacitors and 8 denotes MOS switchesfor inputting clamp potentials. Clamp circuits are constituted by theclamp capacitors 7 and the MOS switches 8. Reference numerals 9 to 12denote switching MOS transistors; 13, minimum value detectiondifferential amplifiers (minimum value detection circuits); and 14,maximum value detection differential amplifiers (maximum value detectioncircuits). Voltage follower circuits are constituted by the respectivedifferential amplifiers. Reference numeral 15 denotes minimum valueoutput MOS switches; 16, maximum value output MOS switches; 17, ORgates; 18 and 19, constant-current MOS transistors; and 20, a scanningcircuit. A source follower circuit with NMOS in a final stage is used inthe minimum value detection circuits 13, and a source follower circuitwith PMOS in a final stage is used in the maximum value detectioncircuits 14. Reference numeral 21 denotes a common output line throughwhich an AF signal from a pixel is outputted.

In this circuit configuration, it is possible to eliminate a reset noisegenerated in the photodiode and FPN generated in the sensor amplifier,the maximum value detection circuit, and the minimum value detectioncircuit by providing noise clamp circuits of a feedback type inpre-stages of the minimum value detection circuits 13 and the maximumvalue detection circuits 14.

In addition, a minimum value of a video signal can be obtained byproviding a voltage follower circuit of a source follower type for eachpixel in a final output stage, and turning off a constant-current sourceof an output stage of each voltage follower at the time of output ofmaximum value to commonly connect the voltage follower circuits to anoutput line connected to the constant-current source. In addition, aserial video signal can be obtained by turning on the constant-currentsource of the output stage of each voltage follower at the time ofoutput of AF signal to connect the voltage follower circuitssequentially to the output line. According to this operation, since themaximum value detection circuit also serves as an AF image signal outputcircuit, it becomes possible to miniaturize a chip.

FIGS. 4A to 4D show specific circuit diagrams of a differentialamplifying circuit of a pixel portion, a source follower circuit, adifferential amplifying circuit of the maximum value detection circuit,and a differential amplifying circuit of the minimum value detectioncircuit in the AF sensor circuit. FIG. 4A is a circuit diagram of thedifferential amplifying circuit of the pixel portion (corresponding tothe differential amplifying circuit 3 of FIGS. 3A and 3B), FIG. 4B is acircuit diagram of the source follower circuit 6, FIG. 4C is a circuitdiagram of the minimum value detection circuit 13, and FIG. 4D is acircuit diagram of the maximum value detection circuit 14.

In addition, a specific circuit configuration of each circuit is shownin FIGS. 4A to 4D. An MOS transistor is used in all the circuits.Reference numerals 41 to 46 in each circuit of FIGS. 4A to 4D denote MOStransistors to be constant-current sources. In this embodiment, at thetime of operation of the AF sensor circuit, the MOS transistors are usedas the constant-current sources by applying a signal for operating theMOS transistors within a linear operation range to gate. In addition, atthe time of non-operation of the AF sensor circuit, a bias current isturned off by applying a signal for cutting off the MOS transistors tothe gate.

More specifically, a control signal to be applied to the gates isgenerated in the T/G circuit according to communication from themicrocomputer, and control signals AFON1 to AFON7 and control signalsAF2ON1 to AF2ON7 shown in FIGS. 1A and 1B are supplied to correspondingAF sensor circuits, respectively. The AF sensor circuit is brought intoan operating state by applying a control signal (intermediate levelsignal) for operating the MOS transistors 41 to 46, which constitute theconstant-current source as described above, within the linear operationrange, to the respective gates of the MOS transistors 41 to 46.

On the other hand, the AF sensor circuit is brought into a non-operatingstate by applying a control signal (in the case of AFON1 to AFON7, a VDDlevel signal (power source level signal), and in the case of AF2ON1 toAF2ON7, a GND level signal) for cutting off the MOS transistors 41 to46, to the respective gates of the MOS transistors 41 to 46. Note thatthe control signals AF2ON1 to AF2ON7 are supplied to all the circuits ofFIGS. 4A to 4D, and the control signals AF2ON1 to AF2ON7 are supplied tothe circuit of FIG. 4C only.

FIG. 5 shows a specific example of a logarithmic transformation type AEsensor circuit (including a photodiode). This corresponds to all AEsensor circuits including the AE sensor circuits S1 to S7 of FIGS. 1Aand 1B. In FIG. 5, reference numeral 500 denotes a PN junctionphotodiode; 501, a PN junction diode functioning as a nonlinear elementfor performing logarithmic compression; and 502, a differentialamplifying circuit of CMOS structure. In addition, in FIG. 5, a specificcircuit configuration of the differential amplifying circuit 502 is alsoshown. The differential amplifying circuit 502 is constituted using MOStransistors, and among the MOS transistors, those denoted by 47 and 48are PMOS transistors to be constant-current sources.

By controlling the MOS transistors 47 and 48, operation andnon-operation of the AE sensor circuits are controlled. Morespecifically, as shown in FIGS. 1A and 1B, control signals AEON1 toAEON7, AEONT, AEONW, and AEONM are supplied to corresponding AE sensorcircuits, respectively, from the T/G circuit based on control of themicrocomputer. The control signals AEON1 to AEON7 correspond to the AEsensor circuits S1 to S7, respectively, the control signal AEONTcorresponds to the AE sensor circuit T, the control signal AEONWcorresponds to the four AE sensor circuits W1 to W4, and the controlsignal AEONM corresponds to the four AE sensor circuits M1 to M4.

Here, at the time of non-operation of the AE sensor circuit, the MOStransistors 47 and 48 are turned off by applying a control signal of aVDD level (power source level) to respective gates of the MOStransistors 47 and 48, and the AE sensor circuits are brought into anon-operating state by turning off a bias current of the differentialamplifying circuit 502. In addition, at the time of operation of the AEsensor circuits, the AE sensor circuits are brought into an operatingstate by applying a control signal (intermediate level signal) forcausing the MOS transistors 47 and 48 to operate within a linearoperation range, to the respective gates of the MOS transistors 47 and48.

FIG. 6A shows a specific circuit diagram of an AGC circuit. In thefigure, reference numeral 61 denotes a voltage buffer circuit and 62denotes a comparator circuit. As shown in FIGS. 1A and 1B, AGC circuitsare provided correspondingly to the AF sensor circuits 102 of the AFsensor circuit block 101, and AGC circuits 1 to 7 are providedcorrespondingly to a pair of horizontal linear sensors L1A and L1B to apair of horizontal linear sensors L7A and L7B, respectively.

In each AGC circuit, a maximum value signal from a corresponding AFsensor circuit is impedance-converted in the voltage buffer circuit 61and, thereafter, is compared with a comparison voltage VBB in thecomparator circuit 62. Then, output of the comparator circuit 62 isreversed when the maximum value signal from the AF sensor circuitexceeds the comparison voltage VBB, and accumulation in the photodiodeof the AF sensor circuit is finished.

FIG. 6B shows a specific circuit configuration of the voltage buffercircuit 61, and FIG. 6C shows a specific circuit configuration of thecomparator circuit 62. Reference numerals 63 and 64 denoteconstant-current MOS transistors of the voltage buffer circuit 61, and65 denotes a constant-current MOS transistor of the comparator circuit62. Operation and non-operation of the AGC circuit are controlledaccording to control signals AGCON1 to AGCON7 from the T/G circuit. Asshown in FIGS. 1A and 1B, the control signals AGCON1 to AGCON7correspond to the AGC circuits 1 to 7, respectively.

At the time of operation of the AGC circuit, the constant-current MOStransistors 63 to 65 are operated as constant-current sources byapplying a control signal of an intermediate level from the T/G circuitto respective gates of the constant-current MOS transistors 63 to 65. Onthe other hand, at the time of non-operation of the AGC circuit, theconstant-current MOS transistors 63 to 65 are brought into a current-offstate by applying a control signal of a VDD level (power source level)from the T/G circuit to the respective gates of the constant-current MOStransistors 63 to 65. Operation and non-operation of the AGC circuit arecontrolled in association with operation and non-operation of the AFsensor circuit, and current consumption is reduced by operating only theAGC circuit corresponding to an operated AF sensor circuit.

As described above, biases of the AF sensor circuit and the AE sensorcircuit are controlled independently by the T/G circuit functioning as acontrol circuit. In addition, biases of the AF sensor circuit, the AEsensor circuit, and the AGC circuit are controlled independently by theT/G circuit functioning as a control circuit.

Next, a relationship between zoom ranges (wide-angle range, normalrange, and telephoto range) in actual photographing and operated AFsensor circuits and AE sensor circuits will be described. Table 1 showsa relationship between the zoom ranges and the operated AF sensorcircuits, and Table 2 shows a relationship between the zoom ranges andthe operated AE sensor circuits. In addition, FIGS. 7A to 7C show arelationship between zoom ranges and operated AF sensors and AE sensors.FIG. 7A shows a sensor that operates at the time of wide-angle rangephotographing, FIG. 7B shows a sensor that operates at the time ofnormal range photographing, and FIG. 7C shows a sensor that operates atthe time of telephoto range photographing. Note that, in Tables 1 and 2,checked circuits are circuits in which a bias is turned on, and in FIGS.7A to 7C, circuits in the photodiode areas indicated by slanted linesare circuits in which a bias is turned on. TABLE 1 AF Sensor Zoom rangesL1 L2 L3 L4 L5 L6 L7 (1) Wide-angle range ∘ ∘ ∘ ∘ ∘ ∘ ∘ (2) Normal range— ∘ ∘ ∘ ∘ ∘ — (3) Telephoto range — — ∘ ∘ ∘ — —

TABLE 2 AE Sensor Zoom ranges S1 S2 S3 S4 S5 S6 S7 W1, W2, W3, W4 M1,M2, M3, M4 T (1) Wide-angle range ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ (2) Normal range —∘ ∘ ∘ ∘ ∘ — — ∘ ∘ (3) Telephoto range — — ∘ ∘ ∘ — — — — ∘

First, in the case of the wide-angle range photographing of FIG. 7A, allthe AE sensors (sixteen points of S1 to S7, W1 to W4, M1 to M4, and T)are operated to perform photometry as shown in Table 2, and all AFsensors (seven points of L1 to L7) are operated to perform distancemeasurement as shown in Table 1. Note that the AF sensors L1 to L7 referto the respective pairs of the horizontal linear sensors from L1A andL1B to L7A and L7B shown in FIGS. 1A and 1B.

In the case of the normal range photographing of FIG. 7B, only the AEsensors of S2 to S6, M1 to M4, and T (ten areas) and the AF sensors ofL2 to L6 (five points) are operated to perform photometry and distancemeasurement. The other AF sensors and AE sensors are brought into thenon-operating state. Note that the AF sensors L2 to L6 refer to therespective pairs of horizontal linear sensors from L2A and L2B to L6Aand L6B.

In the case of the telephoto range photographing of FIG. 7C, only the AEsensors of S3 to S5 and T (four areas) and the AF sensors of L3 to L5(three points) are operated to perform photometry and distancemeasurement. The other AF sensors and AE sensors are brought into thenon-operating state. In addition, similarly, the AF sensors L3 to L5refer to the respective pairs of horizontal linear sensors from L3A andL3B to L5A and L5B. The same applies to the embodiments described below.

The selection of the AF sensors in these zoom ranges is performedaccording to a control signal from the T/G circuit under the control ofthe microcomputer as illustrated in FIGS. 4A to 4D. For example, in thecase of the wide-angle range photographing, a signal (intermediate levelsignal) for linearly operating the MOS transistors constituting theconstant-current sources is applied to all the AF sensor circuits,whereby all the AF sensor circuits are operated to perform distancemeasurement.

In addition, the selection of the AE sensors is also performed accordingto a control signal from the T/G circuit as illustrated in FIG. 5. Forexample, in the case of the wide-angle range photographing, a controlsignal (intermediate level signal) for linearly operating the MOStransistors constituting the constant-current sources is applied to allthe AE sensor circuits as described above, whereby all the AE sensorcircuits are operated to perform photometry. Further, as illustrated inFIGS. 6A to 6C, only the AGC circuits corresponding to the operated AFsensor circuits are operated according to a control signal from the T/Gcircuits and the AGC circuits corresponding to the non-operating AFsensor circuits are brought into the non-operating state, therebyperforming the selection of the AGC circuits. In the case of thewide-angle range photographing, since all the AF sensor circuitsoperate, all the AGC circuits are operated.

As described above, in this embodiment, only the necessary AF sensorcircuits and AE sensor circuits among the plurality of AF sensorcircuits and AE sensor circuits are brought into the operating state,and the other AF sensor circuits and AE sensor circuits are brought intothe non-operating state by turning off the constant-current sourcesthereof, whereby current consumption can be reduced significantly. Inaddition, since the current consumption can be reduced, it becomespossible to mount the apparatus of the present invention on a compactcamera, and a solid-state image pickup apparatus for autofocus with lowpower consumption can be realized. Note that the present invention canbe applied not only in the case of the CMOS sensor but also in the caseof, for example, CCD, BASIS, SIT, CMD, or AMI sensor.

Second Embodiment

FIGS. 8A and 8B is a diagram showing a second embodiment of thesolid-state image pickup apparatus for photometry and distancemeasurement of the present invention, and FIG. 9 is a layout plan viewthereof. In this embodiment, the number of divisions of an AE sensor ismade fewer than that of the first embodiment. That is, the AE sensor isconstituted with an AE sensor circuit for entire photometry W and sevenAE sensor circuits for spot photometry S1 to S7. Reference symbol W inan AE sensor photodiode area 103 shown in FIG. 9 corresponds to aphotodiode of the AE sensor circuit for overall photometry W, andsymbols S1 to S7 correspond to photodiodes of the AE sensor circuits forspot photometry S1 to S7, respectively. The other components areconfigured in the same manner as those in the first embodiment shown inFIGS. 1A and 1B.

Table 3 shows a relationship between zoom ranges (wide-angle range,normal range, and telephoto range) of a photographing lens and operatedAF sensors and AE sensors in the second embodiment. TABLE 3 AF Sensor AESensor Zoom ranges L1 L2 L3 L4 L5 L6 L7 S1 S2 S3 S4 S5 S6 S7 W (1)Wide-angle range ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ (2) Normal range — ∘ ∘ ∘∘ ∘ — — ∘ ∘ ∘ ∘ ∘ — ∘ (3) Telephoto range — — ∘ ∘ ∘ — — — — ∘ ∘ ∘ — — ∘

First, in the wide-angle range photographing, all the AE sensors (eightareas) and AF sensors (seven points) are operated to perform photometryand distance measurement. In the normal range photographing, only the AEsensors of S2 to S6 and W (six areas) and the AF sensors of L2 to L6(five points) are operated to perform photometry and distancemeasurement. In the telephoto range photographing, only the AE sensorsof S3 to S5 and W (four areas) and the AF sensors of L3 to L5 (threepoints) are operated to perform photometry and distance measurement.Selection between operation and non-operation of the AF sensors and theAE sensors is performed according to a control signal from the T/Gcircuit as in the first embodiment. In addition, a selection operationof the AGC circuits is performed in association with operation andnon-operation of the AF sensor circuits.

As described above, in this embodiment, as in the first embodiment, onlythe necessary AF sensor circuits and AE sensor circuits among theplurality of AF sensor circuits and AE sensor circuits are brought intothe operating state, and the other AF sensor circuits and AE sensorcircuits are brought into the non-operating state by turning offconstant-current sources thereof, whereby current consumption can bereduced significantly. In addition, since the number of AE sensors isreduced, the structure of the solid-state image pickup apparatus can besimplified and power consumption can be further reduced.

Third Embodiment

Next, a third embodiment of the present invention will be described. Inthe third embodiment, operating AF sensors and AE sensors are differentwith respect to zoom ranges (wide-angle range, normal range, andtelephoto range) as compared with the first embodiment. The structure ofthe apparatus is the same as that in the first embodiment. Table 4 showsa relationship between the zoom ranges and the operated AF sensors, andTable 5 shows a relationship between the zoom ranges and the operated AEsensors. TABLE 4 AF Sensor Zoom ranges L1 L2 L3 L4 L5 L6 L7 (1)Wide-angle range ∘ — — ∘ — — ∘ (2) Normal range — ∘ — ∘ — ∘ — (3)Telephoto range — — ∘ ∘ ∘ — —

TABLE 5 AE Sensor Zoom ranges S1 S2 S3 S4 S5 S6 S7 W1, W2, W3, W4 M1,M2, M3, M4 T (1) wide-angle range ∘ — — ∘ — — ∘ ∘ ∘ ∘ (2) Normal range —∘ — ∘ — ∘ — — ∘ ∘ (3) Telephoto range — — ∘ ∘ ∘ — — — — ∘

First, in the case of the wide-angle range, the AF sensors of L1, L4,and L7 and the AE sensors of S1, S4, S7, W1 to W4, M1 to M4, and T areused. In the normal range, the AF sensors of L2, L4, and L6 and the AEsensors of S2, S4, S6, M1 to M4, and T are used. In the telephoto range,the AF sensors of L3 to L5 and the AE sensors of S3 to S5 and T areused. Selection between operation and non-operation of the AF sensorsand the AE sensors is performed according to a control signal from theT/G circuit as in the first embodiment. In addition, a selectionoperation of the AGC circuits is performed in association with operationand non-operation of the AF sensor circuits as in the first embodiment.

This embodiment is characterized in that three-point distancemeasurement is always performed by using only three blocks among sevenblocks of AF sensor circuits. Consequently, although the number ofdistance measurement points at the time of wide-angle photographingdecreases, current consumption can be further reduced as compared withthe first embodiment. In addition, current consumption can also bereduced by using only a part of the AE sensors rather than using all theAE sensors. Therefore, a compact camera with a long battery life can berealized by using the solid-state image pickup apparatus of thisembodiment in a compact camera of a popular class that does not requirea large number of distance measurement points.

In the above-mentioned first to third embodiments, the solid-state imagepickup apparatus may have, other than a structure in which a current iscompletely cut off in the non-operating state, a structure in which inthe non-operating state a current is supplied in an amount smaller thanthat in the operating state.

Fourth Embodiment

Next, an image pickup apparatus using the solid-state image pickupapparatus having the photometry circuit blocks and the distancemeasurement circuit blocks described in the first to third embodimentswill be described. FIG. 10 is a block diagram showing an embodiment inthe case in which the solid-state image pickup element for describingthe fourth embodiment is used in a lens shutter digital compact camera(image pickup apparatus). In the figure, reference numeral 201 denotes abarrier serving as both a protect for a lens and a main switch; 202, alens for imaging an optical image of an object on a solid-state imagepickup element 204; 203, an iris for varying an amount of light thatpasses through the lens 202; and 204, a solid-state image pickup elementfor capturing an object image thus imaged by the lens 202 as an imagesignal.

In addition, reference numeral 205 denotes the solid-state image pickupapparatus for photometry and distance measurement described in the firstto third embodiments. Here, for example, the solid-state image pickupapparatus for photometry and distance measurement of the embodimentshown in FIGS. 1A and 1B is used. Reference numeral 206 denotes an imagepickup signal processing circuit for processing an image pickup signaloutputted from the solid-state image pickup element. Reference numeral207 denotes an A/D converter for analog-digital converting an imagesignal, a photometry signal, and a distance measurement signal outputtedfrom the solid-state image pickup element 204 or the solid-state imagepickup apparatus 205; 208, a signal processing unit for performingvarious kinds of correction and data compression on the image dataoutputted from the A/D converter 207; 209, a timing generation unit foroutputting various timing signals to the solid-sate image pickup element204, the image pickup signal processing circuit 206, the A/D converter207, the signal processing unit 208, and the like; 210 a system controland operation unit for performing various arithmetic operations andcontrolling the entire camera; and 211, a memory unit for temporarilystoring image data.

Moreover, reference numeral 212 denotes an interface unit for recordingimage data in and reading out image data from a recording medium; 213, adetachable recording medium such as a semiconductor memory in whichimage data is recorded and from which image data is read out; and 214,an interface unit for communicating with an external computer or thelike.

Next, an operation at the time of performing photography with such alens shutter digital compact camera will be described. When the barrier201 is opened, a main power supply is turned on, a power supply of acontrol system is turned on next, and then a power supply of an imagepickup system circuit such as the A/D converter 207 is turned on.

An arithmetic operation of a distance to an object is performed in thesystem control and operation unit 210 with a trigonometrical distancemeasurement method based on a signal outputted from an AF sensor circuitblock of the solid-state image pickup apparatus 205. Thereafter, anextension amount of the lens 202 is calculated, and the lens 202 isdriven to a predetermined position to be focused.

Subsequently, in order to control an amount of exposure, the signaloutputted from an AE sensor of the solid-state image pickup apparatus205 is converted by the A/D converter 207 and then inputted in thesignal processing unit 208. An arithmetic operation of exposure isperformed in the system control and operation unit 210 based on data ofthe signal. Brightness is judged according to a result of thisphotometry, and the system control and operation unit 210 adjusts theiris 203 and a shutter speed according to the results of the judgment.

Thereafter, main exposure is commenced in the solid-state image pickupelement 204 after exposure conditions are established. When the exposureis finished, an image signal outputted from the solid-state image pickupelement 204 is A/D converted in the A/D converter 207 and written in thememory unit 211 by the system control and operation unit 210 through thesignal processing unit 208. Thereafter, data accumulated in the memoryunit 211 is recorded in the detachable recording medium 213 through therecording medium control I/F unit 212 by the control of the systemcontrol and operation unit 210. In addition, the data may be inputted ina computer or the like directly through the external I/F unit 214. Notethat the solid-state image pickup apparatus for photometry and distancemeasurement of the present invention can be used not only in a digitalcompact camera but also in a silver salt camera and the like. Inaddition, the same effect is obtained also when it is used in asingle-lens reflex camera.

As described above, only necessary photometry circuits and distancemeasurement circuits are operated from among the plurality of photometrycircuits and the plurality of distance measurement circuits, andunnecessary photometry circuits and distance measurement circuits arebrought into the non-operating state, whereby current consumption can bereduced significantly, and a solid-state image pickup apparatus forphotometry and distance measurement with low power consumption can berealized. In addition, operation and non-operation of the accumulationtime control circuit are controlled according to operation andnon-operation of the distance measurement circuit, whereby currentconsumption can be further reduced.

Therefore, the solid-state image pickup apparatus for photometry anddistance measurement described above can be suitably used in a compactcamera, and an autofocus compact camera capable of performingmulti-point distance measurement can be realized. In addition, anautofocus compact camera that has a longer battery life and is more userfriendly than that of the prior art can be realized. Many widelydifferent embodiments of the present invention may be constructedwithout departing from the spirit and scope of the present invention. Itshould be understood that the present invention is not limited to thespecific embodiments described in the specification, except as definedin the appended claims.

1. A sensor device for AE/AF comprising: a first photoelectricconversion circuit which has a photoelectric conversion area and is usedfor performing focus adjustment; a second photoelectric conversioncircuit which has a photoelectric conversion area and is used forperforming exposure amount adjustment; and a control circuit whichcontrols a power supply such that power is supplied to said firstphotoelectric conversion circuit and said second photoelectricconversion circuit independently, wherein said first photoelectricconversion circuit and said second photoelectric conversion circuit areformed on a same semiconductor substrate.
 2. A sensor device for AE/AFaccording to claim 1, wherein each of said first and secondphotoelectric conversion circuits includes a current blocking circuitwhich blocks a current, and said control circuit controls said currentblocking circuit.
 3. (canceled)
 4. (canceled)
 5. A sensor device forAE/AF according to claim 1, further comprising: an image pickup elementwhich picks up an object image; and an adjustment circuit which performsfocus adjustment based on a signal from said first photoelectricconversion circuit and performs exposure amount adjustment based on asignal from said second photoelectric conversion circuit. an adjustmentcircuit which performs exposure amount adjustment based on a signal fromsaid first and second photoelectric conversion circuits and performsfocus adjustment based on a signal from said third to sixthphotoelectric conversion circuits. 6.-13. (canceled)
 14. A sensor devicefor AE/AF comprising: a first photoelectric conversion circuit includinga photoelectric conversion area and a logarithmic compression circuit; asecond photoelectric conversion circuit that is provided on one side ofsaid the first photoelectric conversion circuit and has a plurality ofphotoelectric conversion areas and a reading-out circuit for reading outpeak signals of the plurality of photoelectric conversion areas; and acontrol circuit for controlling a power supply such that power issupplied to said first photoelectric conversion circuit and said secondphotoelectric conversion circuit independently, wherein said first andsecond photoelectric conversion circuits are formed on a samesemiconductor substrate.
 15. A sensor device for AE/AF according toclaim 14, wherein each of said first and second photoelectric conversioncircuits includes a current blocking circuit which blocks a current, andsaid control circuit controls said current blocking circuit. 16.(canceled)
 17. A sensor device for AE/AF according to claim 14, furthercomprising: an image pickup element which picks up an object image; andan adjustment circuit which performs exposure amount adjustment, basedon a signal from said first photoelectric conversion circuit andperforms focus adjustment based on a signal from said secondphotoelectric conversion circuit.